These slow cooker caramelized onions have all the rich flavor with minimal effort. Caramelized onions are a great addition to countless dishes. They add depth and complexity to your meals, turning the ordinary into the extraordinary. While stovetop caramelization requires constant attention and can take up valuable time, this slow cooker method allows you to achieve that perfect deep color without the hassle. Add these crock pot caramelized onions to burgers, sandwiches, dips, soups, and salads.

Easy Slow Cooker Caramelized Onions

I love caramelizing onions. Seriously! If you follow me on instagram, you can see me caramelizing onions in my stories at least once a month. When I am making just one onion, it makes sense to caramelize it on the stove top. Occasionally, I come back to the pan, give it a good stir and then go back to whatever else I was doing.

It normally takes about 45 minutes to caramelize an onion on the stove. However, the time increases dramatically once you start adding more onions. Onions have a lot of liquid in them so they take a while to break down. If you are someone like me who loves adding caramelized onions to your meals, then once in a while it makes more sense to cook 5lbs on onions in a large batch and then freeze them for later use.

If you were to cook 5lbs of onions on the stove top, it would takes several hours of frequent stirring to achieve perfect caramelized status. Instead, you can just throw them all into a large slow cooker or crock pot and let them slowly cook for about 12-16 hours. Start it in the early evening one night, and then they will be ready the following afternoon.

Here are the main steps for slow cooker caramelized onions

Preparation: Peel and thinly slice the onions. The slow cooker allows you to be lazy—no need to worry about precision here.
Layering: Place the sliced onions in the slow cooker, drizzle with olive oil and butter, and sprinkle with a pinch of salt. If you like, add a touch of sugar to enhance the caramelization process. I do not use sugar in my recipe, but some people like it.
Set and Forget: Cover the slow cooker, set it to low heat, and let the magic happen. Stir occasionally if you can, but it’s not necessary. The onions will gradually transform over the next 12 hours, intensifying in color and flavor.
Patience Pays Off: The slow cooker method is all about patience. As the onions caramelize, their natural sugars develop, creating a sweet and savory blend of flavors. The long, slow cooking process ensures that each slice reaches its full potential.
Storage: Once your onions have reached that perfect caramelized state, let them cool before transferring them to airtight containers. They can be refrigerated for up to a week or frozen for longer storage.

Ways to Enjoy Slow Cooker Caramelized Onions:

Burgers and Sandwiches: Elevate your burger game by adding a generous spoonful of caramelized onions. They also make a delicious topping for grilled cheese or panini sandwiches. Check out this recipe for Pork and Apple Burgers topped with Caramelized Onions.
Pizza: Spread a layer of caramelized onions on your pizza crust for a sweet and savory twist.
Soups and Stews: Enhance the flavor of your favorite soups and stews by stirring in a scoop of slow cooker caramelized onions.
Salads: Add a burst of sweetness to your salads by tossing in some caramelized onions.
Dips and Spreads: Blend caramelized onions into cream cheese or sour cream for a delectable dip or spread. Perfect for entertaining or snacking.
Pasta and Risotto: Toss caramelized onions into your favorite pasta or risotto dishes for an extra layer of flavor. Pair them with creamy sauces for a match made in culinary heaven. Check out this recipe for Lamb Pulao with Caramelized Onions.

Helpful Tips for Caramelized Onions

If you are slow cooking a large amount of onions, a lot of water will come out of the onions. I like to cook this on low for about 10-12 hours, and then I put the heat on high and slow cook for the remaining time with the lid slightly ajar.
Slow cooking onions will give you brown onions with a luxuriousness richness, but they will not give you the same crispy edges that the traditional stove-top recipe will give you. If you would like crisp edges, I suggest slow cooking in a large batch and then, when you are ready to use your onions, add them to a pan for about 10 minutes and you will have the results you want.
I freeze my caramelized onions in these soupercube containers. I like freezing them in 1/2 cup and 1 cup containers. These containers are amazing. They are silicone and the frozen onions come right out when you are ready to use them. They are safe in the freezer for at least 3 months.

How to make Caramelized Onions in your Slow Cooker

INGREDIENTS

5 lbs Yellow Onions You can also use a blend of onions. Each of my onions was a full pound on it’s own so I ended up using 5 onions.
2 tbsp Salted Butter
2 tbsp Olive Oil extra virgin
1/2 tsp Sea Salt
1 tbsp Balsamic Vinegar optional

INSTRUCTIONS

Peel and thinly slice the onions. The slow cooker allows you to be lazy—no need to worry about precision here. I like to start by cutting each onion in half down the middle, and then making thin slices from each half.
Place the sliced onions in the slow cooker, drizzle with olive oil and place the butter on top. Sprinkle with a pinch of salt. If you like, add a touch of sugar to enhance the caramelization process. I do not use sugar in my recipe, but some people like it.
Cover the slow cooker, set it to low heat, and let the magic happen. Stir occasionally if you can, but it’s not necessary. The onions will gradually transform over the next 12 -16 hours, intensifying in color and flavor.
If you are slow cooking a large amount of onions, a lot of water will come out of the onions. I like to cook them on low for about 10-12 hours, and then I put the heat on high and slow cook on high for the remaining time with the lid slightly ajar.

NOTES

Slow cooking onions will give you brown onions with a luxuriousness richness, but they will not give you the same crispy edges that the traditional stove-top recipe will give you. If you would like crisp edges, I suggest slow cooking in a large batch and then, when you are ready to use your onions, add them to a pan for about 10 minutes and you will have the results you want.